Leukaemia is a cancer that starts in
blood-forming tissue such as the bone marrow, which makes blood cells (red blood
cells that carry oxygen around the body, white blood cells that fight disease
and infection, platelets that help to stop bleeding when it starts).

In people with leukaemia, the bone marrow produces large numbers of abnormal
white blood cells and not enough normal red blood cells.

Leukaemia cases represent less than 4% of all cancer cases in adults but are
the most common form of cancer in children.

There are
different types of leukaemia
(e.g. acute, chornic, myeloid and lymphoid leukaemia).